Act enthusiastically on the French voyage (3,3)
I believe the answer is:
let rip
'act enthusiastically' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'on the french voyage' is the wordplay.
'on' says to put letters next to each other.
'the french' becomes 'le' ('the' in French).
'voyage' becomes 'trip' (I've seen this in another clue).
'le' next to 'trip' is 'LET RIP'.
Can you help me to learn more?
(Other definitions for let rip that I've seen before include "Vent feelings" , "Speak violently - allow to tear" , "Speak without restraint" , "Act violently" , "Go wild" .)